Lethargic Man (anag.)

This is waaay beyond my ability. I asked my father if he could do it for me and he said yes; after a couple of months of occasional prodding, he said:

"It's not likely to be done in the near future, I'm afraid. The project requires considerable planning and design of a circuit board, which takes a huge time. There are considerations beyond the obvious such as designing and applying a suitable power supply (even if I do use an off-the-shelf unit), designing an enclosure and assembling it, to say nothing of designing and fabricating a PCB with no more than Letraset PCB transfers and copper chloride. I don't think you quite realise what it involves. If you can find an off-the-shelf kit solution, I'd be happy to do that for you as that would take an evening or two.

After half an hour of casting around on the Internet, I began to wonder if I was tackling this the right way. So I applied Lateral Thinking—what I really should have done in the first place (hindsight is, of course, always 20/20)—and tried cranking the sample rate up as high as it could go, in the hope I might capture the high frequency spikes as sampled data rather than aliasing noise, and lo and behold, a clean signal.

I suspect there's more to it than that—I get an almost clean signal at 32 kHz, but an aliased one at 44.1 kHz—but if the hat fits^*...

* As yet, only proven for ten second clips of three tracks; but hopefully it'll extend to the lot.

Thanks for all your help anyway; it was interesting learning about what they did inside the box, and if I hadn't had you to tell me I was listening to aliasing noise rather than mains hum, I might still be at square one on this.